Double labelling of blanched neurons in the central nervous system of the rat by retrograde axonal transport of horseradish peroxidase and iron dextran complex.

The retrograde axonal transport of an iron-dextran complex leads to a labelling of neural cell bodies in the central nervous system (CNS) of the rat. This tracer and horseradish peroxidase (HRP) can both be demonstrated histochemically in same cell bodies of intralaminar thalamic neurons in the central lateral nucleus, after injection of iron-dextran in the striatum and injection of HRP in the motor cortex. This is made possible by processing the sections first for HRP and then for ferric ions by Perl's reaction. This method allows an accurate demonstration of divergent axonal projections and is compatible with cytoarchitectonic studies on the same sections.